History of Whole Dry Soybeans - Page 1
by William Shurtleff and Akiko Aoyagi
A Chapter from the Unpublished Manuscript, History of Soybeans and
Soyfoods, 1100 B.C. to the 1980s
©Copyright 2004 Soyfoods Center, Lafayette, California
Whole dry soybeans, the kind known to most people, are soybeans that have come to maturity and dried on the plants in the fields, prior to harvest. They can be classified according to the color of their seed coat as yellow, black, green or white; according to the season of maturity as early, mid-season, or late; according to the seed size as small, medium, or large, and, as explained in the last chapter, as vegetable-type soybeans (which have a mild or slightly nutty flavor and cook more easily) and field-type soybeans (which generally have a slightly more "beany" flavor and do not cook as easily). Yellow soybeans, by far the most common type (more than 98% of the total) and the only type that is traded, have a straw-yellow seed coat. Regardless of the seed coat color, most soybeans have yellow cotyledons (meats), however some soybeans with green or black seed coats have light green dry cotyledons. Some yellow soybeans have a black hilum, the "eye" or seed scar.
In this chapter we will only discuss whole dry soybeans that are soaked, boiled or baked, and served in a non-dry form. Whole soybeans that are dry roasted or deep-fried to make soynuts or germinated to make sprouts are the subject of the next two chapters.
Etymology . The etymology of the term "soybean" in various languages is given in Chapter 3. In general usage in most languages, whole dry soybeans are simply called "soybeans" in that language. In China, differences in seed coat color have long been important. Thus "soybeans" are dadou ("great beans"), but "yellow soybeans," the most popular type, are huang-dou ("yellow beans"), "black soybeans" are wu-dou or hei-dou , and "green soybeans" are ch'ing-dou . Likewise in Japan, "soybeans" are daizu ("great beans"), but the only other type with a popular name is "black soybeans," which are called kuromamé (literally "black beans"), never kuro daizu ("black soybeans"). This shift in terminology is indicative of the fact that in much of East Asia black soybeans, which are used both medicinally and as foods in rather different ways from typical yellow soybeans, are often thought of as almost a different food. Likewise in the West, black soybeans are often sold at Oriental food stores labeled "black beans" rather than "black soybeans."
In English, the terms "dry soybeans" or "mature soybeans" have been used since the early 1900s to distinguish whole dry soybeans from fresh green soybeans. Whole dry soybeans with yellow, green, or black seed coats are called "yellow soybeans," "green soybeans," and "black soybeans" respectively.
HISTORY OF WHOLE DRY SOYBEANS IN EAST ASIA
Since ancient times in East Asia, soybeans have been harvested just before the beans and pods are fully dried to prevent loss of beans by their shattering from the pods. Harvesting in the morning, when the pods are still moist with dew, was also done to prevent shattering. The plants were typically cut just above the ground with a hook-shaped knife or sickle, but in some parts of China farmers wrapped their hands in old cloth and pulled up the plants from the ground. The plants were then allowed to further dry and cure, for several days to several months, either in shocks in the fields, or on a dirt threshing floor, or (in Japan) by hanging the plants in bundles upside down over horizontal raised bamboo poles. Most farmhouses or small villages had a threshing floor, a patch of smooth, hard-packed ground about 50 feet square. There the beans would be removed from the pods, either by flailing them with bamboo flails, by having a donkey or horse pull a small stone roller (2 1/2 feet long and 6 inches in diameter) or log over the plants, or by beating the plants over a stone. The beans were then separated from the pods and other refuse by winnowing. A small wooden fork or shovel was used to throw the threshed material into the air over the threshing ground on a windy day. The chaff was carried away by the wind. After cleaning, the seeds were typically poured on matting and placed in the sunshine for 3-5 days, then stored or sold in bags made of rice straw. In China each bag typically held 97 kg (213 lb) and in Japan 60 kg (132 lb) of soybeans. In Manchuria the sacks were often stored in osier binds, whose walls were made of strips of rice straw matting about 15 inches wide. As the bin was filled with sacks, the strips were gradually wound around until a height of about 20 feet was reached, holding some 450 sacks. The roof of the bin consisted of bundles of rice or millet straw, overlapping one another like shingles. Bins were generally located next to the threshing ground (Carson 1909; Shaw 1911; Dorsett and Morse 1928-31, 1944, 1950).
In most parts of East Asia whole dry soybeans have never been widely used as such, as baked, boiled, or refried beans, in the way that we in the West, for example, cook navy, pinto, or kidney beans. Rather they are transformed into a host of other foods that generally bear little resemblance to the original beans. These include tofu, soymilk, soy sauce, miso, and the like, and they are the most popular soyfoods even though the extra processing raises their price.
There are good reasons that the people of East Asia prefer not to eat soybeans as such. First, because of their high protein content and low starch content, soybeans require much longer cooking than most other beans, generally 5-6 hours without pressure (but only 25-30 minutes at 15 pounds pressure), and even after this they never get as soft as most beans. Also, this long cooking uses lots of fuel, which has always been relatively expensive in densely populated areas. Moreover, the water in China is generally hard (rich in calcium), which further increases the required cooking time (Horvath 1927). Second, boiled or baked whole soybeans are more difficult to digest than most other soyfoods and than some other dry beans; the oligosaccharides they contain, which are removed in the processing of most soyfoods, can cause flatulence. And third, most East Asian people prefer the flavor and versatility of other soyfoods. (People in countries that have not traditionally consumed soybeans often describe them as having a "beany" flavor). Yet throughout East Asia, whole dry soybeans have long been used in certain dishes at certain times.
Whole soybeans have found limited use since early times in East Asia as a protein source for livestock, especially work animals. Paillieux (1880) and Li and Grandvoinnet (1912) noted that the black soybean has been used in this way in China and Japan since time immemorial. In Manchuria, the seeds were fed, whole or crushed, mixed with chopped millet straw and a little water. (Fresh green soybeans were reserved for sheep.) Piper and Morse (1916) noted that whole soybeans, sometimes boiled and mixed with straw, barley, or bran, were used occasionally to feed work horses or milk cattle. Horvath (1928) reported that the black soybean had long been preferred to the yellow as a livestock feed since the black was known to contain much less fat than the yellow bean.
China . Because of the unique, ancient, and highly esteemed role that black soybeans have in traditional Chinese medicine, we will discuss them first. As early as the second century BC, the Spring and Autumn Annals noted that black soybeans ( hei dou ) were "suitable for the `yin' or negative principle, while fresh green soybeans were good for the positive principle" (Wu 1848). Wu also stated that ancient pharmaceuticals called for using black soybeans steeped in wine as a good remedy for purifying the blood, curing colds, and strengthening mothers if taken two days after childbirth. To prepare: take 5 pints of selected black soybeans ( wu dou , literally "crow beans"), wash well, and soak in 12 quarts of wine. Fry the beans until the smoke is gone, then steep in grain-based (clear) wine until the latter has turned reddish purple. The ordinary dose is 3 cups during the day or night. The liquid from cooking black or dark soybeans may also be used to make a fermented soybean wine, which Shinoda (1977) believes was developed during the Sung Dynasty (960-1279); see Chapter 39. In Shansi province the extremely black beans, said to be the male beans, were thought to be especially good medicinally.
As noted above, black beans were the preferred type for livestock. Paillieux (1880) reported that during a famine, a handful of black soybeans would keep a person alive. Hosie (1901) enumerated four varieties of black soybean ( wu dou ) grown in Manchuria; large black ( da wu dou , which has a green interior), small black, and large and small flat black ( pien wu dou ). Embrey and Wang (1921) identified only two types: regular black ( wu dou ) and small black ( hsiao hei dou ). But according to Shaw (1911) only 3.4% of the soybean grown in Manchuria were black soybeans, versus 80.1% yellow. Stuart (1911) in his Chinese Materia Medica stated:
Medicinally, the black beans are considered to have much value. Their frequent use is thought to have a most beneficial effect upon the body, giving strength and vigor, albeit with heaviness. This latter fact is the only objection offered to the use of these beans. They are regarded as an admirable counterpoison against most of the vegetable poisons . . . The black kind is not much used as food, as it is thought to render the body heavy.
Today black soybeans continue to be widely used in Chinese medicine; they are considered to be slightly yang . The most widely used preparation involves cooking black soybeans in excess water with small red dates and gingerroot to make a strong soup, widely used by women for centuries as a blood builder. Another preparation ( tan tou ch'i or "Semen Sojac Praeparatum") consists of black soybeans cooked with various herbs, lightly fermented, then dried for sale at herb shops. This is simmered with onions and used to make a tea, used at the beginning stages of a cold, especially for children who are weak or prone to sickness. We know of no research that has tried to identify the active medicinal principle in black soybeans or to show how, specifically, they differ from yellow soybeans.
There are numerous mentions of soybeans being used as such as food in China before the Christian era. In the I Li , ( Ceremony and Ritual ) originally written prior to 770 BC, although there are no clear references to soybeans, there is mention of ch'iu , a food later described as being made from rice and soybeans boiled together. In the Chou Li ( Rituals of Chou ) of the third century BC, there is again reference to ch'iu as well as to the "Five Grains" or "Nine Grains," which later commentators say included soybeans. The first specific reference to soybeans as a food appeared in the Li Chi ( The Book of Rites ), written by the disciples of Confucius in the second or third century BC. "Tzu Lu said `Alas how dreadful is poverty when in life one has nothing to eat and in death one has nothing for a funeral ceremony.' Confucius replied: `If you eat soybeans and drink water, you can be entirely satisfied . . . " The T'ung Yueh^, written by Wang Po in about 59 BC stated "Slaves should receive only rice and (soy) beans, and drink water. They should not drink wine."
There are many references after the beginning of the Christian era. The Han Shu ( History of the Han Dynasty ), written in about AD 90 stated:
At the present time, when there is a famine and the people are poverty stricken, half their diet consists of soybeans (shu) and when food for the soldiers was scarce, soybeans were mixed with other grains and eaten by them . . . Soybeans are also boiled and used as piao, an outside coating or garnish for food.
Tsao Chih (AD 192-232), a famous poet wrote in a poem: "Make a fire of the stalks and cook the (soy) beans. They are both from the same root" (Wu 1848). It should be noted that most of these early references suggest that the soybean was used as such as food primarily by poor people or in time of famine or hardship.
After the fifth century AD the soybean was mentioned in various materia medica. The Ming i pieh lu by T'ao Hung-ching (452-536) stated that if yellow or white soybeans were eaten for a long period of time, they would cause the body to become heavy. Yet when cooked in a meal-like form they taste good and sweet, and are a good remedy for many diseases (six were cited). The Shih liao pen tsao by Meng Shen of the seventh century noted that the soybean had a "cold effect" upon the human system, but when mixed with rice and pounded into a powder, it could be used as a remedy for many diseases. The T'u Ching Pen Tsao (date unknown??) stated that the white soybean was never used medicinally like the black soybeans, except when soaked in wine, it made a remedy for the cure of colds (Wu 1848). Wu also stated that soybeans with a green seed coat were smoked, then called "tea beans" ( ch'a tou ). According to Shinoda (1977), from ancient times until 1912, there was a custom of cooking soybeans and azuki beans at temples on April 8 (Buddha's Birthday), then giving them to people who visited the temple that day. This was called the "custom of giving away soybeans to create good karma." Adolph, in the early 1920s, did a nutritional analysis of a soybean-millet bread ( wo-wo-t'ou or p'a-ku ), which he said was popular in China. He also analyzed black soybeans.
Horvath (1927), a Russian scientist doing soy research in China, gave a lengthy summary of the research done worldwide on using soybeans as a food and urged the adoption of the baking soda cooking technique by the people of China, where he had long lived and worked. He noted that baking soda (sodium bicarbonate) belongs to the natural products of China, being collected in Mongolia from soda lakes.
If soda were used in China for boiling the soybean soft, thus doubling its digestibility (especially when passed through a sieve, which raises its protein digestibility from 60%-90%), it may revolutionize the nutrition of the Chinese population, because an amount of food equal in nutritive value to tofu would be obtained for half the price.
Horvath also recommended the use of a pressure cooker when one was available, noting that "cooking at a temperature above the boiling point breaks up the cellulose structure and develops a richness of flavor that is not obtainable with the lower temperature." In addition, Horvath found the average composition of 30 Manchurian soybeans to be 8.6% moisture, 19.9% fat, and 42.8% protein. Yellow soybeans were generally the richest in fat and protein (especially fat), followed by green, then black soybeans, which had the least.
Little is known of the extent of use of whole soybeans in China since 1949, although they have never been widely consumed, as such, in China. Morse and Cartter (1952) reported that mature soybeans may be boiled with soy sauce, then sun-dried for use as a snack, or boiled and eaten with millet, grain sorghum, or rice. Shurtleff (1983b) found soybeans sold canned in a sauce in Beijing.
Japan . Little is known of the early history of using whole soybeans as such as foods in Japan. The reference to soybeans in the Kojiki of AD 716?? (described in detail in Chapter 8) seems to suggest that soybeans were being used as food by that early date. In early times in mountain villages having little access to seafoods, soybeans are said to have been called yama-no-maguro ("tuna of the mountains"). For a long time, there have been four famous recipes for serving whole soybeans. All involve simmering the beans in a syrup of water, shoyu (soy sauce), and sugar to make a rather sweet or "candied" product which stores well without refrigeration and is used as a side dish with rice. The recipes are Gomoku Mamé (literally "five colored beans," which also contains five diced land-and-sea vegetables), Budo Mamé (literally "grape soybeans" because of the sweet, rich flavor), Kombu Mamé (containing strips of kombu, a sea vegetable), and Kuro Mamé (made with black soybeans; a favorite at New Year's). Each of these preparations is both prepared at home and sold commercially in packaged, ready-to-eat form. Another distinctive Japanese way of using whole soybeans is as fresh soybean puree, called go in Japanese, written with the character also pronounced kureru , meaning "to give." Indeed fresh soy puree "gives" all the different types of tofu and soymilk. In homes, it is made by grinding soaked soybeans in a serrated earthenware mortar ( suribachi ), then used as the base for a vegetable-rich hearty soup called Gojiru , or made into deep-fried dumplings called Bakudan-agé . Recipes for all the above Japanese preparations are given in The Book of Tofu (Shurtleff and Aoyagi 1975).
Black soybeans ( kuro mamé ) are widely used in Japan. In feudal times, spies ( ninja ), skilled in the art of ninjutsu or "invisibility" are said to have prized a very nutritious and lightweight dry food made of roasted black soybeans and sesame seeds, ground together. They carried this in a pouch. As in China, black soybeans have long been known for their medicinal and health-giving properties. They have long been eaten on New Year's day as a way of wishing the consumer good health for the coming year. However by about 1900, the main way of serving black soybeans was candied, simmered in sugar, water, and shoyu, to be eaten as a side dish with rice (Rein 1899; Oshima 1905).
The first Japanese nutritional analysis of soybeans was done by Oshima in 1905. He found that the bean consisted of over 4% indigestible crude fiber, and that human beings could digest the following percentages of the basic nutrients in Budo Mamé (candied whole soybeans, see above): protein only 62%, fat only 35-38%, and carbohydrates including fiber 81-90%. More recently Kudo et al. (1979) Asahimatsu Foods have been granted a patent for using cooked and pureed soybeans as a cheese extender.
Other East Asia . In Korea, whole dry soybeans are fairly widely cooked with millet, grain sorghum, or rice. In Indonesia they are used only rarely?? In Vietnam the stalks of the plant were traditionally used to make a sort of incense (Bui 1905).
HISTORY OF WHOLE DRY SOYBEANS IN EUROPE AND AUSTRALIA
Early Developments (1793-1899) . The earliest known European reference to using whole dry soybeans as food was by Loureiro in 1793. "Uses: These seeds, having been boiled or lightly toasted, are quite acceptable to both the stomach and the palate." It is not clear whether or not Loureiro tasted them himself. In 1876 the Bulletin de la Société d'Acclimatation printed a letter from the Secretary of the Society for Horticulture near Etampes, France. It reported:
This grain leaves nothing to be desired. As for quality, it is perfect. In order to judge it well, we have cooked it in the dry state and tasted it seasoned only with a little salt. Prepared in this way it tastes something like a haricot [green bean], lentil, or pea. It is very tender and doubles exactly in volume when cooked in excess water. It is easily digested. This legume must be boiled for a long time before it becomes very tender.
During the late 1870s extensive research on the food uses of whole dry soybeans was conducted by Haberlandt and co-workers in Austria and nearby countries (see Chapter 49). Haberlandt (1878) ground the soybeans to form fine grits, and cooked them with other foods such as mashed potatoes and rice, or wheat grits and milk, or mashed potatoes; he called the preparation Sojenta , since it resembled the Italian national food Polenta . He also recommended the use of soybeans in place of peas in Pea Sausage and other military foods. Professor Hecke of Vienna encouraged the use of soybeans with potatoes and developed a number of tasty, nutritious recipes. Co-workers Leithner, Erttel, Baumgartner, and Mach each developed different recipes, which they praised. Mach pureed them, and found them superior to peas or lentils. Leithner complained that they were not easily cooked soft. Dr. Johannes Leunis praised their good taste (Haberlandt 1878).
In 1880 Paillieux in France wrote about whole soybeans and developed recipes, finding the flavor "sweet and very pleasant" in salads and pureed in soups. He recommended soaking the beans for 24 hours before cooking and to add 0.3% baking soda to the cook water, both to aid tenderization and reduce cook time. Paillieux and Bois (1884), Lecerf (J.G. 1888), Le Goff (1911) and numerous others recommended the baking soda technique. In subsequent publications Mr. Blavet (Ref?? who??) recommended adding the beans to boiling water, leaving them for 2-3 minutes, then cooking them in new water. We now know that this would reduce flatulence-causing oligosaccharides and beany flavor, with little loss of protein. In 1888 Lecerf reported the use of soybeans in breads and biscuits for diabetic diets (J.G. 1888); much subsequent work in this area was done by Egasse, Dujardin-Beaumetz, and other physicians and many nutritional analyses were given, as described in Chapter 21, Nutrition.
1900-1939 . From 1900-1919 Le Goff wrote four articles on the use of soybeans in diabetic diets. He encouraged the French to grow their own soybeans and gave recipes for this use in diabetic diets: whole dry soybeans with butter; soybeans sauteed with vegetables; cooked soybean puree; and bread or cake with soybeans. In 1910 the French-Chinese soyfoods pioneer Li Yu-ying applied for a British patent (granted in 1912) calling for dehulled soybeans to be cooked, ground to a paste, and mixed with sugar. Dried fruits, chestnuts, almonds, cocoa, etc. could be added to make sweet paste resembling chestnut butter ( creme de marron ) for making pastry or confections. By 1910 or 1911 Li was making this sweet Creme de Soya and in 1912 he and Grandvoinnet described it and related soy confectionery products in their classic Le Soya , noting that the soy products lasted longer and were easier to digest than chestnut butter, containing only 13.4% fat. Luethje (1914-15) lamented that soybeans do not become soft even after long cooking.
Von Noorden and Salomon (1920) found that boiling soybeans in hard water (rich in calcium) causes the soy protein and the calcium to form an insoluble compound that makes the beans hard and prevents full protein digestion. Baking soda can be used to soften hard water and greatly increase bodily assimilation of soy protein and ash/minerals (Horvath 1927). Trabut (1927) found that pressure cooking is the way to cook soybeans. "The results passed my hopes and by this rapid and economical process of soaking for 24 hours then cooking for 15 minutes, the soybean becomes a legume superior to the Haricot in most points. It contains more protein than most animal protein sources." Bois (1927) felt that whole soybeans were best served in the form of a puree.
1940-1982 . Very little work was done with whole dry soybeans from the late 1920s until the late 1950s. Then Granose Foods, a Seventh-day Adventist company in England, introduced Canned Soya Beans in Tomato Sauce. A similar product was introduced to Australia in 1954 by Sanitarium Foods Co., also an Adventist company.